AuroraWatch UK, which has 150,000 followers on Facebook, issued the alert after the staff member’s lawnmower interfered with a sensor used to look for signs of the natural electrical phenomenon which creates a spectacular coloured light display in the sky.

Lancaster University

The magnetometer, situated in the university grounds, measures the changes in the earth’s magnetic field.

A spokeswoman for the university said: “When an aurora is potentially visible from the UK, our magnetometers record a disturbance in the magnetic field and alerts are automatically sent out to our followers.

“Unfortunately, auroras (Northern Lights) aren’t the only thing that can cause such changes to the measured magnetic field.

“In this instance, the ride-on lawnmower’s electric motor created its own local magnetic field and, because it was driven near to our magnetometer, we recorded this disturbance and sent out an alert.”

A blog post on Aurora Watch UK’s website, which is run by scientists in the Space and Planetary Physics group at Lancaster University’s Department of Physics, and has 90,000 email subscribers, read: “We believe the interference was caused by university staff mowing the grass on a sit-on mower.

“We’ll work with the facilities team to try and avoid an incident such as this occuring in the future!”

The incident occured on August 23.

The university spokeswoman added: “Some of our users may have noticed that it was only the Lancaster magnetometer that registered this disturbance; if it really was an aurora causing this change in the earth’s magnetic field we would expect all of our magnetometers (which are located throughout the UK) to also register it.

“The AuroraWatch UK team manually cancelled the alert within minutes on Facebook and followed up with a cancellation email and detailed blog post.

“Interference from gardening equipment is not something we have had an issue with before but now it has happened we are going to take steps to make sure it doesn’t happen again by working with our grounds maintenance team.”

AuroraWatch UK is a free service offering alerts of when the aurora might be visible from the UK.

People can sign up to the service by visiting the AuroraWatch UK website http://aurorawatch.lancs.ac.uk/alerts.